A trajectory planning decision method for low-altitude penetration and obstacle avoidance scenarios

Abstract

The present application belongs to the technical field of aircraft automatic flight control system design, and particularly relates to a trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios. The method comprises step T1, determining whether there is a new mountain range ahead of the aircraft along the original flight path, and if there is a new mountain range, comparing the decision altitude of the new mountain range with the original flight path altitude; step T2, if the decision altitude of the new mountain range is higher than the original flight path altitude, calculating the radar detection probability based on the decision altitude; step T3, when the radar detection probability is greater than a set value, performing a turning maneuver according to a predetermined turning maneuver algorithm, otherwise, performing a climbing maneuver according to a predetermined climbing maneuver algorithm. The present application improves the aircraft avoidance effect and effectively enhances the survivability of large aircraft.

Description

Technical Field

[0001] The present application belongs to the field of flight control technology, and in particular relates to a trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios. Background Art

[0002] The goal of low-altitude penetration technology research is to develop flight control technology that enables aircraft to perform ultra-low-altitude maneuvers, effectively avoiding mountains, buildings, and various threats, thereby improving flight safety and mission survivability. Low-altitude penetration technology can be categorized into terrain following, terrain avoidance, threat avoidance, and terrain following / terrain avoidance / threat avoidance technologies.

[0003] Terrain following involves maneuvering within the vertical plane, following the contours of the terrain at a predetermined minimum altitude, utilizing the terrain for cover and offering a superior penetration method. Terrain avoidance involves maneuvering within the azimuth plane, flying around tall obstacles such as mountains. This low-altitude penetration method leverages terrain cover, making it less likely to be detected by the enemy, but carries a higher probability of collision with terrain obstacles. Threat avoidance involves maneuvering within the azimuth plane to avoid enemy detection and air defense attacks, allowing the aircraft to close closely to the target and enhance the accuracy and surprise of weapon delivery.

[0004] Through terrain following / terrain avoidance / threat avoidance technology, the aircraft maneuvers within the azimuth plane based on the predetermined range, and performs comprehensive maneuvers near the predetermined heading, flying around mountains, avoiding threats, and following terrain contours.

[0005] Low-altitude penetration technology, including obstacle avoidance decision-making methods, primarily involves terrain avoidance. Since the 1980s, numerous countries have conducted extensive research on low-altitude penetration technology. Engineers such as Sabi J. Asseo employed a variational method combined with the steepest descent method to solve a three-dimensional optimal path, improving convergence but not guaranteeing a global optimal solution. Engineers such as MC Waller employed a dynamic programming optimization method, using thrust and heading as control variables for planning, but simulation results showed that the storage capacity was excessive. Engineers such as Yuan Weidong proposed a dynamic programming method combined with a tree search method, effectively addressing the curse of dimensionality. However, this dynamic programming method may not yield a global optimal solution. Robert employed a trajectory planning technique called sparse A* search, incorporating path constraints to effectively reduce the search space to a level that allows real-time convergence, but the trajectory search is limited to a two-dimensional plane. Furthermore, several researchers have applied ant colony algorithms to aircraft path planning, but these algorithms suffer from slow search speed and are prone to falling into local optima. Summary of the Invention

[0006] In order to solve at least one of the above technical problems, this application designs a trajectory planning decision method for low-altitude penetration and obstacle avoidance scenarios, which mainly includes:

[0007] Step T1: Determine whether there is a new mountain range ahead of the aircraft along the original flight path. If there is a new mountain range, compare the decision altitude of the new mountain range with the altitude of the original flight path.

[0008] Step T2: If the decision altitude of the new mountain range is higher than the original track altitude, then the radar detection probability is calculated based on the decision altitude;

[0009] Step T3: When the radar detection probability is greater than a set value, a turning maneuver is performed according to a predetermined turning maneuver algorithm; otherwise, a climbing maneuver is performed according to a predetermined climbing maneuver algorithm.

[0010] Preferably, step T1 further comprises:

[0011] Capture the peak height of new mountains detected;

[0012] A flight clearance safety altitude is added to the altitude to form a new mountain range decision altitude for comparison with the original track altitude. The flight clearance safety altitude can be any value between 100m and 140m.

[0013] Preferably, in step T2, calculating the radar detection probability includes:

[0014] When crossing a new mountain range at this decision altitude, the radar detection probability is set to 30% when the aircraft is flying below 100 meters and unobstructed. When the aircraft is flying above 1000 meters and unobstructed, the radar detection probability is set to 100%. When the aircraft is flying between 100 and 1000 meters, the radar detection probability is determined using a linear function calculated from the two points above.

[0015] Preferably, in step T3, the set value is 50%.

[0016] Preferably, in step T3, performing a turning maneuver according to a predetermined turning maneuver algorithm includes:

[0017] (1) Before executing the predetermined turning maneuver algorithm, if the aircraft has not made any turning or climbing movements, the aircraft shall calculate the turning decision point A based on the aircraft's minimum turning radius, obstacle width, and the preset safety margin value, and change the track direction at point A to make the turn. When the aircraft passes through the midpoint C that is consistent with the initial track at the turning decision point A during the turn, a new track planning decision shall be made based on whether there is a new mountain range.

[0018] (2) If the aircraft is currently executing a turning maneuver based on the trajectory planning decision before executing the predetermined turning maneuver algorithm, the new predetermined turning maneuver algorithm is executed at point C where the turning maneuver is currently being executed;

[0019] (3) Before executing the predetermined turning maneuver algorithm, if the aircraft is performing a climbing maneuver according to the trajectory planning decision, maintain the current flight altitude and execute the new predetermined turning maneuver algorithm.

[0020] Preferably, calculating the turning decision point A includes:

[0021] S = Wx + r + b;

[0022]

[0023] Where, S is the distance between point A and the new mountain range, Wx is the obstacle width, r is the minimum turning radius of the aircraft, Va is the aircraft speed, is the turning bank angle of the aircraft, b is a preset safety boundary value, taking any value between 100 and 140 m.

[0024] Preferably, in step T3, performing the climbing maneuver according to the predetermined climbing maneuver algorithm includes:

[0025] (1) Before executing the predetermined climbing maneuver algorithm, when the aircraft has no turning or climbing action, calculate the climbing decision point E according to the distance between the aircraft and the new mountain range obstacle, the height of the new mountain range obstacle, and the flight speed, and perform a climbing action at point E. During the climbing process, make a new trajectory planning decision in real time according to whether there is a new mountain range;

[0026] (2) Before executing the predetermined climbing maneuver algorithm, if the aircraft is performing a turning maneuver or a climbing maneuver according to the trajectory planning decision, perform the climbing maneuver according to the new predetermined climbing maneuver algorithm.

[0027] Preferably, calculating the climbing decision point E includes:

[0028] Set the distance membership function: a1 = 3 / L1 (when L1 < L, a1 = 1);

[0029] Set the speed membership function: Vh = Va * tanγ, a2 = Vh / Vh0 (when Vh > 5 m / s, a2 = 1);

[0030] Where, L1 = norm(Pa - Px), Pa is the aircraft position, Px is the obstacle position, γ = atan(Hx / L), Va is the aircraft speed, Hx is the obstacle height, L is the distance critical value, which is used to represent that when γ takes the maximum value γ max = 15°, the aircraft must perform a climbing maneuver at the distance critical value L, Vh0 is the speed critical value, which is used to represent that after the vertical speed component of the aircraft exceeds this speed critical value, the radar detection probability of the aircraft can exceed the set value;

[0031] When a1 >= a2, calculate the climbing decision point E based on the distance membership function. The expression for the distance Lj1 between the climbing decision point E and the obstacle is: Lj1 = Hx / tanγ max ;

[0032] When a1 < a2, calculate the climbing decision point E based on the speed membership function. The expression for the distance Lj2 between the climbing decision point E and the obstacle is: Lj2 = Hx * Va / Vh0.

[0033] The trajectory planning decision method for the low - altitude penetration and obstacle avoidance scenario of this application can complete the obstacle avoidance trigger logic decision, obstacle avoidance maneuver decision, climbing maneuver decision point judgment decision, turning maneuver decision point judgment decision, and algorithm exit logic decision, improving the aircraft's obstacle avoidance effect and effectively enhancing the survival ability of large aircraft. Brief Description of the Drawings

[0034] Figure 1 It is a schematic diagram of the decision - making method process of a preferred implementation manner of the trajectory planning decision method for the low - altitude penetration and obstacle avoidance scenario of this application.

[0035] Figure 2 It is a schematic diagram of the turning trajectory planning of this application.

[0036] Figure 3 It is a flowchart of the turning trajectory planning of this application.

[0037] Figure 4 It is a schematic diagram of the climbing trajectory planning of this application.

[0038] Figure 5 It is a flowchart of the climbing trajectory planning of this application.

[0039] Figure 6 It is a schematic diagram of the trajectory when encountering a new mountain range of this application. Detailed Embodiments

[0040] To make the purpose, technical solutions, and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings in the embodiments of this application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below by referring to the drawings are exemplary and intended to explain this application, and should not be construed as a limitation of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the drawings.

[0041] This application provides a trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios, which mainly includes:

[0042] Step T1: Determine whether there is a new mountain range ahead of the aircraft along the original flight path. If there is a new mountain range, compare the decision altitude of the new mountain range with the altitude of the original flight path.

[0043] Step T2: If the decision altitude of the new mountain range is higher than the original track altitude, then the radar detection probability is calculated based on the decision altitude;

[0044] Step T3: When the radar detection probability is greater than a set value, a turning maneuver is performed according to a predetermined turning maneuver algorithm; otherwise, a climbing maneuver is performed according to a predetermined climbing maneuver algorithm.

[0045] In some optional embodiments, step T1 further comprises:

[0046] Capture the peak height of new mountains detected;

[0047] A flight clearance safety altitude is added to the altitude to form a new mountain range decision altitude for comparison with the original track altitude. The flight clearance safety altitude can be any value between 100m and 140m.

[0048] The value of the flight clearance safety height H1 is, for example, 120m. This application sets the flight clearance safety height H1, that is, the flight trajectory and the new mountain range maintain a safety value of at least 120m, and further decisions are made based on the safety value.

[0049] In some optional implementations, in step T2, calculating the radar detection probability includes:

[0050] When crossing a new mountain range at this decision altitude, the radar detection probability is set to 30% when the aircraft is flying below 100 meters and unobstructed. When the aircraft is flying above 1000 meters and unobstructed, the radar detection probability is set to 100%. When the aircraft is flying between 100 and 1000 meters, the radar detection probability is determined using a linear function calculated from the two points above.

[0051] In some optional embodiments, in step T3, the set value is 50%. In this embodiment, the probability of enemy radar detection is determined. If the radar detection probability is greater than 50%, a turning maneuver is performed; if the radar detection probability is less than or equal to 50%, a climbing maneuver is performed. In alternative embodiments, the set value may also be other values such as 45%, 55%, etc.

[0052] In some optional embodiments, in step T3, performing a turning maneuver according to a predetermined turning maneuver algorithm includes:

[0053] (1) Before executing the predetermined turning maneuver algorithm, if the aircraft has not made any turning or climbing movements, the aircraft shall calculate the turning decision point A based on the aircraft's minimum turning radius, obstacle width, and the preset safety margin value, and change the track direction at point A to make the turn. When the aircraft passes through the midpoint C that is consistent with the initial track at the turning decision point A during the turn, a new track planning decision shall be made based on whether there is a new mountain range.

[0054] (2) If the aircraft is currently executing a turning maneuver based on the trajectory planning decision before executing the predetermined turning maneuver algorithm, the new predetermined turning maneuver algorithm is executed at point C where the turning maneuver is currently being executed;

[0055] (3) If the aircraft is performing a climb maneuver based on the trajectory planning decision before executing the predetermined turning maneuver algorithm, the aircraft will execute the new predetermined turning maneuver algorithm while maintaining the current flight altitude.

[0056] First, in case (1), it should be understood that the purpose of calculating the turning decision point A here is to decide whether the system will take over the flight control. When the aircraft has not reached the turning decision point, the pilot can be warned. If the pilot performs a turning operation, the flight will be carried out according to the pilot's decision while maintaining the turning trajectory prompt. Conversely, if the pilot does not perform a turning operation, it is necessary to take over the aircraft at the turning decision point A and perform an autonomous turn; the autonomous turn is executed according to the turning trajectory plan.

[0057] refer to Figure 2 , r is the minimum turning radius, R is the sum of the obstacle radius and the safety value H1, Point A is the tangent point between the circle of radius r and the original route, Point B is the tangent point between the two circles of radius r and R, Point C is the point where the aircraft's nose aligns with the original route, and Point D is the mirror image of Point B through Point C, perpendicular to the route direction, which is also the final turning point. Point A is the turn decision point.

[0058] In some optional implementations, calculating the turning decision point A includes:

[0059] S=Wx+r+b;

[0060]

[0061] Where S is the distance between point A and the new mountain range, Wx is the width of the obstacle, r is the minimum turning radius of the aircraft, Va is the speed of the aircraft, is the aircraft turning slope, b is the preset safety boundary value, and can be any value between 100 and 140m.

[0062] Taking a value of 120m as an example, in this embodiment, the aircraft uses the minimum turning radius and obstacle width as the primary inputs for similarity determination, and begins maneuvering when it is tangent to the obstacle's safety margin. That is, the maneuver begins when the distance between point A and the obstacle is Wx+r+120 meters.

[0063] In addition, in case (1), if Figure 6 As shown in the figure, when the aircraft reaches point C, where the nose of the aircraft is aligned with the original course, the pilot can exit the takeover mode and determine whether there are new mountains ahead. If new mountains are detected ahead, the pilot compares the height of the new mountains with that of the original track.

[0064] When the new mountain range is lower than the original track, the flight continues according to the previous track, that is, the flight continues according to the current turning algorithm; when the new mountain range is higher than the original track, the flight cannot be based on the current turning algorithm, and a new online track planning decision is made; if there is no new mountain range ahead, the current turning algorithm is continued; the algorithm is executed until all obstacles are bypassed, and the flight is based on the previous track and the decision is exited.

[0065] In case (2), if there is a turning algorithm that has been executed, the turning algorithm is calculated for the new mountain range, and the aircraft flies from the current point C to the point C in the turning algorithm of the new mountain range. When arriving at the new point C, it is again determined whether there is a new mountain range ahead and the above decision is executed. The algorithm is executed until all obstacles are bypassed, and the aircraft flies along the previous trajectory and exits the decision.

[0066] In case (3), if the climb algorithm is currently being executed, then: perform the turning algorithm calculation for the new mountain range, maintain the current altitude until the decision point in the new mountain range algorithm; execute according to the turning algorithm, and when reaching the new point C, determine again whether there is a new mountain range ahead and execute according to the above decision; execute the algorithm until all obstacles are bypassed, fly along the previous trajectory and exit the decision.

[0067] The above three situations can refer to the attached Figure 1 There are three specific branch processes of the left turn maneuver.

[0068] In some optional embodiments, in step T3, performing a climbing maneuver according to a predetermined climbing maneuver algorithm includes:

[0069] (1) Before executing the predetermined climb maneuver algorithm, if the aircraft has not made any turns or climbs, the climb decision point E is calculated based on the distance from the aircraft to the new mountain obstacle, the height of the new mountain obstacle, and the flight speed, and the climb maneuver is executed at point E. During the climb, new trajectory planning decisions are made in real time based on whether there is a new mountain.

[0070] (2) Before executing the predetermined climb maneuver algorithm, if the aircraft is performing a turning maneuver or a climb maneuver according to the track planning decision, the climb maneuver is executed according to the new predetermined climb maneuver algorithm.

[0071] In the above situation (1), refer to Figure 4 , the purpose of setting the climb decision point E is also to decide whether to take over the flight by the system. When the aircraft has not reached the climb decision point, an alarm prompt is given to the pilot. If the pilot performs a climb operation, the climb trajectory prompt is maintained. If the pilot does not perform a climb operation, the aircraft is taken over at the climb decision point and autonomous climb is performed; the autonomous climb is executed according to the climb trajectory planning. When the aircraft flies to the peak F of the mountain range, the pilot can choose to exit the takeover mode and at the same time judge whether there is a new mountain range ahead. If a new mountain range is found again ahead, compare the height of the new mountain range with the original track height. When the new mountain range is lower than the original track, continue to fly according to the previous track, that is, enter the descent process according to the current algorithm; when the new mountain range is higher than the original track, it is impossible to execute according to the current climb algorithm, and enter a new online track planning decision; if there is no new mountain range ahead, continue to execute the current climb algorithm, that is, execute the descent maneuver; execute the algorithm until all mountain ranges are crossed, fly along the previous track and exit the decision.

[0072] In situation (2), if there is a currently executed turning or climb algorithm, the climb algorithm is calculated for the new mountain range, and the aircraft flies from the current point to the peak of the new mountain range; when reaching the new peak, judge again whether there is a new mountain range ahead and execute according to the previous decision; execute the algorithm until all obstacles are bypassed, fly along the previous track and exit the decision.

[0073] The above two situations can refer to the two specific branch processes of the right-side climb maneuver in Appendix Figure 1 .

[0074] In some alternative embodiments, calculating the climb decision point E includes:

[0075] Setting the distance membership function: a1 = 3 / L1 (when L1 < L, a1 = 1);

[0076] Setting the speed membership function: Vh = Va * tanγ, a2 = Vh / Vh0 (when Vh > 5m / s, a2 = 1); [[ID=,24]]

[0077] where L1 = norm(Pa - Px), Pa is the aircraft position, Px is the obstacle position, γ = atan(Hx / L), Va is the aircraft speed, Hx is the obstacle height, and L is the distance critical value, which is used to represent that γ takes the maximum value γ maxWhen α = 15°, the aircraft must perform a climbing maneuver at a distance from the critical value L. Vh0 is the speed critical value, which is used to indicate that when the vertical speed component of the aircraft exceeds this speed critical value, the radar detection probability of the aircraft can exceed the set value.

[0078] When a1 ≥ a2, the distance has reached the critical position at this time, and the distance calculation decision point is adopted, that is, the climbing decision point E is calculated based on the distance membership function. The expression for the distance Lj1 between the climbing decision point E and the obstacle is: Lj1 = Hx / tanγ max ;

[0079] When a1 < a2, for example, the set value of the radar detection probability is 50%. Then when a1 is less than a2, it indicates that the radar detection probability of the aircraft is greater than 50%. At this time, the speed should be preferentially used as the input of the decision point, that is, the climbing decision point E is calculated based on the speed membership function. The expression for the distance Lj2 between the climbing decision point E and the obstacle is: Lj2 = Hx * Va / Vh0.

[0080] The trajectory planning decision method for the low-altitude penetration and obstacle avoidance scenario of this application can complete the obstacle avoidance trigger logic decision, the obstacle avoidance maneuver decision, the climbing maneuver decision point judgment decision, the turning maneuver decision point judgment decision, and the algorithm exit logic decision. It has been verified by simulation in a certain type of aircraft and can achieve the avoidance effect, effectively improving the survival ability of large aircraft.

[0081] The following combines with Figure 1 attachment Figure 3 attachment Figure 5 and attachment

[0082] Refer to Figure 1 attachment, the overall trajectory planning decision process for the low-altitude penetration and obstacle avoidance scenario includes:

[0083] S1: The aircraft flies along the original trajectory;

[0084] S2: Detect whether there are new mountains in a certain area. The detection method can be to use the detection equipment of the aircraft itself for detection;

[0085] S3: When new mountains are detected in a certain area, capture the height of the apex of the new mountains;

[0086] S4: Add a safety value to the height of the apex of the new mountains to obtain the apex decision height;

[0087] S5: Make a further decision based on the apex decision height. If the apex decision height of the new mountains is higher than the original trajectory height, enter S6; if the apex decision height of the new mountains is lower than the original trajectory height, enter S19;

[0088] S6: If the new mountain top decision altitude is higher than the original track altitude, determine whether the enemy radar is detectable. If it is detectable, proceed to S7; if not, proceed to S23.

[0089] S7: Determine whether the enemy radar detection probability is greater than 50%. Specifically, at an altitude of 100 meters and without obstructions, the radar detection probability is 30%. At an altitude of 1000 meters or above and without obstructions, the radar detection probability is 100%. The radar detection probability increases as the flight altitude is between 100 and 1000 meters.

[0090] S8: If the enemy radar detection probability is greater than 50%, execute a turning maneuver;

[0091] S9: Determine whether the turning algorithm is currently being executed and proceed to S10 or S20;

[0092] S10: If the turning algorithm is not currently being executed, determine whether the climbing algorithm is being executed and proceed to S11 or S13;

[0093] S11: If the climbing algorithm is currently being executed, add a new mountain turning algorithm;

[0094] S12: Maintain flight altitude;

[0095] S13: If the climbing algorithm is not currently being executed, a new mountain turning algorithm is executed;

[0096] S14: If the aircraft has not reached the turning decision point, the pilot will be warned and prompted to maintain the turning trajectory if the pilot performs a turning operation.

[0097] S15: If the pilot does not perform a turning operation, the system takes over the aircraft at the turn decision point and performs an autonomous turn according to the turn trajectory plan;

[0098] S16: Determine whether the aircraft has reached point C. If the aircraft has not reached point C, proceed to S15. If the aircraft has reached point C with its nose pointing in the same direction as the original heading, proceed to S17.

[0099] S17: Determine whether there is a new mountain range ahead. If there is a new mountain range, go to S3. If there is no new mountain range, go to S18.

[0100] S18: Determine whether the obstacle is bypassed. If the obstacle is not bypassed, proceed to S15. If the obstacle is bypassed, proceed to S19.

[0101] S19: Fly along the original track and exit decision;

[0102] S20: If the turning algorithm is currently being executed, add a new mountain turning algorithm;

[0103] S21: Fly from the current point C to the point C of the new mountain range;

[0104] S22: Go to point C of the mountain range and enter S17;

[0105] S23: Enemy radar cannot detect, execute climbing maneuver;

[0106] S24: Determine whether the turning or climbing algorithm is currently being executed. If not, proceed to S25. If yes, proceed to S31.

[0107] S25: executing the new mountain climbing algorithm;

[0108] S26: If the aircraft has not reached the turn decision point, the pilot will be warned. If the pilot performs a climb operation, the climb trajectory will be maintained. If the pilot does not perform a climb operation, the aircraft will continue to climb until the turn decision point is reached.

[0109] S27: If the pilot does not perform a climb operation, the system takes over the aircraft at the climb decision point and performs an autonomous climb according to the climb trajectory plan;

[0110] S28: Determine whether the mountain top has been reached. If not, continue climbing and proceed to S27. If the mountain top has been reached, proceed to S29.

[0111] S29: Determine whether there is a new mountain range ahead, same as S17. If there is a new mountain range, proceed to S3. If there is no new mountain range, proceed to S30.

[0112] S30: Descend flight altitude and enter S19;

[0113] S31: Currently executing the turning or climbing algorithm, adding a new mountain climbing algorithm;

[0114] S32: Fly from the current point to the top of the new mountain range;

[0115] S33: Determine whether the mountain top has been reached. If not, continue climbing and enter S32. If the mountain top has been reached, enter S29.

[0116] refer to Figure 3 , the process of the turning maneuver algorithm is as follows:

[0117] S41: The aircraft enters a turning maneuver;

[0118] S42: Calculate points A and B based on the aircraft position, aircraft speed, aircraft turning slope, obstacle position, and obstacle width;

[0119] S43: During the turning process, a warning prompt is given;

[0120] S44: Determine whether it is a manual turn. If it is an automatic system turn, proceed to S45; if it is a manual turn, proceed to S55;

[0121] S45: Determine whether the decision point A has been reached. If not, proceed to S43; if so, proceed to S46;

[0122] S46: The system takes over the control management authority;

[0123] S47: The aircraft turns to point B with maximum turning ability;

[0124] S48: Determine the relationship between the maximum turning radius r of the aircraft and the radius R of the obstacle. If r < R, proceed to S49; otherwise, proceed to S56;

[0125] S49: The aircraft flies along the obstacle;

[0126] S50: The aircraft turns. If the original route has not been reached, proceed to S49 until the original heading is reached, then proceed to S51; <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​S63: Determine whether to manually climb. If the system automatically climbs, proceed to S64. If the system manually turns, proceed to S72.

[0140] S64: Determine whether the climb decision point has been reached. If not, proceed to S62. If reached, proceed to S65.

[0141] S65: The system takes over control management authority;

[0142] S66: Climbing algorithm execution;

[0143] S67: Determine whether the mountain top has been reached. If so, proceed to S68; otherwise, proceed to S66.

[0144] S68: Determine whether to exit the takeover mode. If yes, proceed to S69; otherwise, proceed to S73.

[0145] S69: Keep track prompt;

[0146] S70: Determine whether to resume flight on the original flight path. If yes, proceed to S71; otherwise, proceed to S69.

[0147] S71: Exit climb maneuver, system exit;

[0148] S72: Real-time trajectory calculation;

[0149] S73: Descend flight altitude;

[0150] S74: Determine whether to resume flight on the original flight path. If so, proceed to S71; otherwise, proceed to S73.

[0151] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios, characterized in that: Comprising: Step T1, determine whether there is a new mountain range in front of the aircraft flying along the original flight path. If there is a new mountain range, compare the decision height of the new mountain range with the height of the original flight path; Step T2, if the decision height of the new mountain range is higher than the height of the original flight path, calculate the radar detection probability according to the decision height; Step T3, when the radar detection probability is greater than the set value, perform a turning maneuver according to a predetermined turning maneuver algorithm, otherwise, perform a climbing maneuver according to a predetermined climbing maneuver algorithm.

2. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 1 is characterized in that: Step T1 further includes: Capture the vertex height of the detected new mountain range; Based on the vertex height, add a flight clearance safety height to form the decision height of the new mountain range for comparison with the height of the original flight path. The flight clearance safety height takes any value between 100m and 140m.

3. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 1 is characterized in that: In step T2, calculating the radar detection probability includes: When crossing the new mountain range according to the decision height, when the flight height of the aircraft is lower than 100m and there is no occlusion, the given radar detection probability is 30%; when the flight height of the aircraft is higher than 1000m and there is no occlusion, the given radar detection probability is 100%; when the flight height is between 100m and 1000m, determine the radar detection probability according to the linear function calculated by the above two points.

4. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 1 is characterized in that: In step T3, the set value is 50%.

5. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 1 is characterized in that: In step T3, performing a turning maneuver according to a predetermined turning maneuver algorithm includes: (1) Before performing the predetermined turning maneuver algorithm, when the aircraft has no turning or climbing action, calculate the turning decision point A according to the minimum turning radius of the aircraft, the width of the obstacle, and the preset safety boundary value, and change the flight path direction at point A to turn. When passing through the midpoint C that is consistent with the initial flight path at the turning decision point A during the turning process, re-make a new flight path planning decision according to whether there is a new mountain range; (2) Before performing the predetermined turning maneuver algorithm, when the aircraft is performing a turning maneuver according to the flight path planning decision, perform the new predetermined turning maneuver algorithm at the current point C where the turning maneuver is being performed; (3) Before performing the predetermined turning maneuver algorithm, when the aircraft is performing a climbing maneuver according to the flight path planning decision, maintain the current flight height and perform the new predetermined turning maneuver algorithm.

6. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 5 is characterized in that: Calculating the turning decision point A includes: S = Wx + r + b; Where S is the distance between point A and the new mountain range, Wx is the width of the obstacle, r is the minimum turning radius of the aircraft, Va is the speed of the aircraft, is the aircraft turning slope, b is the preset safety boundary value, and can be any value between 100 and 140m.

7. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 1 is characterized in that: In step T3, performing a climbing maneuver according to a predetermined climbing maneuver algorithm includes: (1) Before performing the predetermined climbing maneuver algorithm, when the aircraft has no turning or climbing action, calculate the climbing decision point E according to the distance of the aircraft from the new mountain range obstacle, the height of the new mountain range obstacle, and the flight speed, and perform a climbing action at point E. During the climbing process, make a new flight path planning decision according to whether there is a new mountain range in real time; (2) Before performing the predetermined climbing maneuver algorithm, when the aircraft is performing a turning maneuver or a climbing maneuver according to the flight path planning decision, perform the climbing maneuver according to the new predetermined climbing maneuver algorithm.

8. The trajectory planning and decision-making method for low-altitude penetration and obstacle avoidance scenarios according to claim 7 is characterized in that: Calculating the climbing decision point E includes: Set the distance membership function: a1 = 3 / L1 (when L1 < L, a1 = 1); Set the speed membership function: Vh = Va * tanγ, a2 = Vh / Vh0 (when Vh > 5 m / s, a2 = 1); Where L1 = norm(Pa-Px), Pa is the aircraft position, Px is the obstacle position, γ = atan(Hx / L), Va is the aircraft speed, Hx is the obstacle height, and L is the distance threshold, which is used to indicate that γ takes the maximum value γ max =15°, the aircraft must perform a climb maneuver at the distance threshold L. Vh0 is the speed threshold, which indicates that after the vertical velocity component of the aircraft exceeds this speed threshold, the aircraft's radar detection probability can exceed the set value. When a1>=a2, the climb decision point E is calculated based on the distance membership function. The distance Lj1 between the climb decision point E and the obstacle is expressed as: Lj1=Hx / tanγ max ; When a1 < a2, calculate the climb decision point E based on the speed membership function. The expression for the distance Lj2 between the climb decision point E and the obstacle is: Lj2 = Hx * Va / Vh0.

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